Insulated leer roller



April 12, 1932-- E. W. PAXTON ET Al.

INSULATED LEER ROLLER Filed March 8, 1950 F'lgv.

F195. mw vx@ /lo Patented Apr. 12, 1932 UNITED STATES PATENT oFFlcEELISHA W. IAXTON ANDI .ARTHURv W. SCHMID, F WASHINGTON, PENNSYLVANIA,

ASSIGNORS T0 HIGHLAND-WESTERN GLASS COMPANY, OF WASHINGTON, PENN-SYLVANIA, A CORPORATION 0F DELAWARE INSULATED LEER ROLLER Applicationfiled March -8,

This invention relates to improvements in supportlng rolls for sheetglass in glass annealing leers and it is among the objects thereof toprovide improved supporting rolls ,for

sheet glass annealing leers which are adapted transverse thermal balanceduring the coolelevation of the leer ing or annealing period.

Another object of the invention is the provision of a roll structureadapted to control the heat losses in a manner to produce proper thermalconditions at the surface of the rolls which contact with the glasssheet.

Another object of the invention is the provision of roll structures andthe application of cooling media thereto which shall provide positivemeans for controlling the heat losses from the hot sheet materialsupported thereby, and from the contacting portions of the rolls.

These and other objects will become more apparent from a considerationof the accompanying drawings in which like reference charactersdesignate like parts and in which Fig. 1 is a cross sectional lview ofan improved form of roll forsheet glass annealing leers embodying theprinciples of this invention; Figs. 2 and 3 are similar views ofmodications of the invention; Fig. 4 a cross sectional view of anothertype of roll designed to function in accordance with the stated objectsof the invention; Fig. 5 a similar'view of another modication of theroll; Fig. 6 a longitudinal sectional view of a portion of a glassannealing leer showing the customary arrangement of the glass supportingrolls; and Fig. 7 a cross sectional view partially in structure shown inFig. 6.

With reference to Figs. 6 and 7 of the drawings, 1 designates the roofor top wall of a glass annealing leer; 2 the side walls; 3 rolls whichare preferably driven by suitable actuating mechanism; 4 designates thebottom wall of the leer and 5 designates the wall which cooperates withthe bottom wall 4 to form a. heating or cooling flue employed in 1930.serial No. 432,329.

-controlling the temperature within the muie or leer chamber,

In the operation of the leer, the sheet glass 1s entered at the passage7 and is conveyed longitudinally of the leer by the rolls 3 on which thehot sheet glass is supported; and during its travel through the leer thesheet is subjected to the proper annealing or cooling temperatures untilit nally is discharged from the leer in the proper annealed and cooledstate.

In the application of a roll type of leer to the manufacture ofcontinuous sheet glass, the sheet glass is conducted from the sheetforming pass of the forming rolls directly into the annealing leer andif the thermal conditions of the forming rolls are balanced, the glasswill be of substantially uniform temperature transversely of its length.

It has been found that ydue to the construction of metal sheetsupporting rolls with solid ends andshafts, as heretofore employed, itis difficult to maintain the sheet glass in transverse thermal balanceduring lts passage through the leer, this being partially due to thelarge loss of heat from the axial sections of the supporting rolls.Since the rolls are essentially journalled at their respective ends, theeasiest path of travel of heat from the rolls is by conduction throughtheir ends, and on account of the relatively heavy journals, heat lossis greater at or near the ends of the rolls. For this reason it has beennecessary in the prior art to supply additional heat in the annealingchambers toward the edges of the glass sheet in an effort to neutralizethe loss of heat at these points.

This method has undesirable features such as diiiiculty ofv controllingthe corrective heating; necessity of .continual regulation; cost offuel; additional length of leer necessary to properly dissipate theadded heat, and the fact that its whole purpose has been correctiverather than preventive.

In accordance withv the present invention, the proper thermal balancetransverse of the sheet is maintained by the inherent structuralcharacteristics of the supporting rolls and without the necessity ofadding any heat to the leer adjacent the ends of the rolls, with itsattendant requirement of additional leer length to dissipate such addedheat.

With reference to the drawings in Fig. 1, the roll 3 is shown asprovided with a central spider 8 which is optional and for mechanicalsupport only, and4 end spiders 9 which are formed integrally with ormounted on a hollow shaft 10. The spokes of the spiders are of minimumcross section and constitute relatively small heat conducting paths fromthe roll shells 3 that are in contact with the hot glass 11 which theysupport, to the roll shafts 10.

In accordance with the present invention, an insulating or bafflestructure, generally designated at 13, is provided at the ends of therolls 3 and is in spaced relation with the rolls as shown at 14. Thebattle structure may consist of any suitable material of relatively lowheat conducting qualities, as for example, asbestos, and this can mostconveniently be provided in the form of a series of discs 15 which arearranged in the manner shown and held in their respective positions byan end collar 16.

VViththis arrangement, it will be seen that a relatively free heatradiating space is provided at the central portionof the rolls and thebale structure 13 isetfective in producing a muile effect that sets up aheat lag which greatly impedes the heat radiation at the portions of therolls adjacent the baille member. Since, as previously explained, theloss of heat from the roll shell through conductivity to its shaft isreduced to a minimum, it remains only to offset or neutralize thatminimumby utilization of available radiation and for this purpose theroll construction is specifically designed to provide for radiation fromshell to shaft nearthe center of the rollstructure. p

By employing the hollow shafts 10,- the temperature of the rolls may befurther controlled by conducting a suitable cooling Inedium, such as airor water, through thehollow shafts. Since the maximum heat radiationfrom roll shell to shaft is effected at the central portion of the roll,as explained above, the corresponding portion of the hollow shaft willbe the hottest and by setting up a forced circulation of cooling mediumin the shaft the heat is removed from the shaft by conduction andconvection and con sequently from the roll shell by radiation andconvection, at this central portion. By controlling the length of thebaille structure 15 in accordance with the ph sical Vdimensions andthermal properties o the roll, and the width and temperature of thesheet glass, a transverse thermal balance may be effectively produced ormaintained in the sheet glass 11 throughout the annealing range of theleer.

In Figs. 2 and 3 are illustrated modifications of the form of bafflestructure as shown in Fig. 1, for example, in Fig. 2 the asbestos sheetdiscs are of gradually decreasing diameter, thus forming a conicalshaped baffle which increases the width of the space 14 so as to obtaina gradual increase of heat radiation towards the cent-er of the roll.This is equally obtainable by a structure shown in Fig. 3 in which theair gap or space between the roll and baflie structures is varied byassembling a series of discs of different diameters to produce the stepsor sections 17.

As shown in Fig. 4, the roll may he constructed without the use ofbattles of the type described in connection with Figs. 1,2 and 3, tobring about a maximum loss of heat at the central portion of the rolls.This may be effectively obtained by supporting the rolly3 on a hollowshaft 18 having an expanded central portion 19 which is in contact withthe roll 3. Disposed in the roll is a conduit 20 leading to the expandedportion of the hollow shaft. This conduit functions to conduct a coolingmedium to the interior of the roll which is passed out through therespective ends of the hollow shaft and maintains a cooling effect onthe center portion of the roll structure similar to that obtainable bythe provision of means for controlling and/or localizing the heatradiation as hereinbefore explained.

In the modification shown in Fig. 5, the roll 3 is provided with ahollow shaft 10 having a bushing 21 interposed between the roll and theshaft, which bushing is of substantial length and provides a maximumsurface area of contact with the roll 3 to produce a maximum loss ofheat through conduction at its central portion. The bushing 21 may beprovided with grooves 22 of variable size, depth, and/or spacing, toreduce its conduction capacity near the ends thereof so that the loss ofheat is gradually tapered off from the center in the direction of theends of the roll.

It is apparent from the foregoing description of this invention thatproper thermal balance may be obtained transversely of the sheet glassby controlling the loss of heat by means of suitable construction anddesign of the leer rolls, namely, by so constructing said rolls thattheir heat conducting and radiating properties are controlled. By theuse of this invention, the annealed glass is of a more nearly uniformquality and free from strains and no applied/heat is necessary tomaintain the proper thermal conditions in the al1- nealing leer duringthe critical or annealing range of the glass.

Although one embodiment of the invention has been herein illustrated anddescribed, it will be obvious to those skilled inthe art that variousmodications may be made in the details of construction without departingfrom the principles herein set forth.

WVe claim:

1. A roller for conveying sheet material through an annealing chambercomprising a roll-shellka shaft supported in said shell con-v nectionsfor said shell and shaft Whic are adapted to minimize the loss of heatby conduction from the shell to said shaft and baillev means foreffecting radiation of heat at the center of the roll-shell and forcontrollin the amount of heat radiation from shell tos aft through thelength ofthe said shell.

an annealing chamber, each comprising a roll-shell, a shaft forjournalling said shell,l means for supporting said roll-shell and shaftin radially spaced relation and insulating meansv disposed between saidshaft and the said shell out of contact with the latter, and adjacentthe end of the rolls to reduce the heat radiation losses from the rollshell to the shaft 'adjacent the ends of the rollshells.v

3. Rollers/for an annealing chamber, each comprising a roll-shell, ashaft fbr journalling said shell, means for supportin shaft in radiallyspace ing bushings disposed between said roll shell and shaft` forreducing the heat radiation losses adjacent the ends of the roll. 4. Ona roll structure for conveying sheet material through an annealingchamber, the combination with a roll shell of a supportin shaft thereforand means on said s aft an in spaced relation with said shell forcontrolling the loss of heat through conduction and heat radiation toobtain a thermal balance between the roll-shell and consequently'in thesheet material supported thereon.

In testimony whereof we have hereunto set our hands this 30th day ofJanuary, 1930.

ELISI-IA, W. PAXTON. ARTHUR W. SCHMID.:v

relation, and insulat- 2. Rllers for supporting sheet material insupporting sheet'material in l said roll-shell and` l

